@TerribleBPthrower This is more third hand information so I don't want to speculate too much. From what I can surmise, it started with a blister on his pitching hand. When he came back he couldn't locate with accuracy or velocity. They pulled him out of action for 2 months and started working through his mechanics from the ground up--shortening his leg kick, working on repeatability of his actions (I'm a hitting Mom so forgive me if I've muddled some of the terms). The crazy part is prior to COVID he was slated for an MLB debut so it just highlights how precarious and fraught this journey is (https://www.cbssports.com/mlb/...35055/mackenzie-gore). Apparently it was a huge surprise to many that he pitched in the ACL as soon as he did...and did as well as he did even though, in their words not mine, it's expected for an almost major-leaguer pitching against a bunch of rookies. :-)
One of my son's old teammates also is battling through a bad case of legitimate yips. It started with a non-baseball related health incident in the fall that took him off the field for a while and shook his overall confidence. His first outing on the mount once he was back, he hit 6 batters in a row...and this is a kid known for being able to place pitches and for pitching in high-stress situations. He red-shirted. To work through, he's had to discover himself outside of baseball and start from the beginning. The parents just want their self-confident kid back healthy and whole. If he can figure out the pitching part, even better. Luckily his coach is being very understanding (D1). I know some programs would not be as patient. He pitched a few innings in the Ripken league but it has been months and each outing is still a big deal.
As a Mom, my heart feels for each and every one of these situations. Whether a kids is struggling at the youth, HS, college or professional level...they are all still essentially kids. You just want them all to be able to put their best foot forward no matter what that may be.